IntroductionIntracranial collision tumors are rare diseases in which two distinct neoplasms are found at the same location. We present an unusual case of an intracranial collision tumor composed of atypical meningioma (WHO grade II) and glioblastoma.Presentation of caseThe case was a 56-year-old woman hospitalized due to generalized weakness and dizziness. Imaging survey revealed a right frontal lobe extra-axial mass with significant perilesional edema. The patient underwent a one-stage craniotomy for tumor removal. The pathology revealed collision brain tumors of clear cell atypical meningioma (WHO grade II) and glioblastoma. The patient had an uneventful postoperative recovery.Clinical discussionThe mechanism behind collision brain tumors remains unclear, and some experts consider these tumors sporadic events. Further research is needed to optimize preoperative diagnosis and surgical strategy for collision brain tumor patients.ConclusionSurgeon should consider intracranial collision tumors when brain image indicated unusual perilesional edema of meningioma. Though there is no standard treatment for these patients, it seems one-staged surgical treatment is feasible. To our knowledge this is the first case of collision tumors with clear cell atypical meningioma (WHO grade II) and glioblastoma.